How contractors get estimates and change orders signed

The paperwork that protects a job

Remodelers, electricians, plumbers, roofers, landscapers and other contractors get paid on a handful of documents:

• The estimate or quote: what you will do and for how much. Write it in the estimating tool you already use, save it as a PDF, and the client approves it by signing.
• The job contract: scope, price, payment schedule, start and completion dates, materials and warranty.
• Change orders: every change to scope or price once the job has started.
• The completion sign-off: the client's acceptance that the punch list is done.
• Subcontractor agreements, for the trades you bring in.

Each one is a PDF of up to 8 MB that you send for signature, and a document can have up to 20 signers, so both owners of a home can sign it.

Change orders: where payment disputes start

A client asks you to move three outlets and upgrade the tile. You agree on the spot, do the work, and the extra line on the final invoice is disputed: "we never agreed to that price". A verbal yes or a text message leaves the price and the scope open to argument.

A signed change order puts the answer on record. When the client signs with Attest, their passkey, a cryptographic key only they control, unlocked with Face ID, Touch ID, Windows Hello or the device PIN, signs a statement that names the change order's fingerprint (a SHA-256 hash, a short code calculated from the file's contents) and the time. The completed change order is anchored on Horizen, a public blockchain, whose block time shows when. Change one byte of the document, of any signer's entries or of the signed pages, and verification fails. So the signed copy shows which price the client approved, for which work, and when.

Send each change as its own document, and write the job contract's verification code (ATT-XXXX-XXXX, printed on its signed copy) into it, so anyone reading the change order can open the contract it changes at attest.datahubz.com/verify.

Signing in the driveway

You don't have to wait for the client to get home to a computer: they sign on their phone, and you release the document from yours. Signing runs in the web browser, on a phone or a computer, with nothing to install:

1. On your computer (with your signing key already set up), click New agreement, attach the change order PDF and add the client's email address. You can prepare it before you head out to the job.
2. Click Next: place the fields, place a Signature and a Date signed field for the client, and click Create and send.
3. The client opens the email on their phone, taps Review and sign and, the first time, sets up a passkey with Face ID or their phone's PIN.
4. The change order is end-to-end encrypted, so Attest can't hand it over. You release it from your phone: tap Unlock it for … in Attest's email, confirm, and approve with your passkey, and the client's page opens it by itself.
5. The client reviews it and taps Sign with your passkey. When everyone has signed, you both get a link to its certificate, and you each download the same sealed copy.

A client who has signed with Attest before opens the next document at once, with no release step. If you sign too, check Add me as a signer (sign in-app, no email); with In order under Signing order you choose whether you sign first or last.

Estimates that expire

An estimate is only good while your prices hold. Set Expires (optional), for example 30 days out: if the client hasn't signed by then, the estimate closes, no one can sign it, and every party is emailed. Reminders go out every 3 days by default, or every day, every 2 days or every week, at most 5 times.

If a client passes on an estimate, click Void on its row while it is still open: the client is emailed that it was withdrawn, and a document voided before anyone has signed it goes back to your allowance.

What you and the client keep

Every party downloads the same sealed PDF: the signed pages, with a "Signed with Attest" stamp on each signature and a seal line at the foot of every page, a certificate of completion, the audit trail up to completion and a "Verify it yourself, without us" page, with the full evidence, the original document and a standalone verifier attached inside.

Each signature stamp carries the agreement's verification code, the signing date and a QR code, and scanning the QR code opens the agreement's certificate, so a printed copy in the job file leads anyone to the record. The stamp shows where the record is; it doesn't prove a printed page is unaltered. To check a copy, compare it with the signed PDF, or drop the PDF on attest.datahubz.com/verify, where it is fingerprinted in your browser and never uploaded. The open-source verifier attached inside the PDF runs in any browser, even if Attest is gone, and checks each signer's passkey signature, the original document, the pages you see and Attest's anchored record on Horizen.

Give each document a plain title, such as "Change order 3", rather than the client's address: by default its certificate is public and shows anyone with its link or code details such as the title, the file name and each signer's name and signing time, never the document. Choose Private when you send to keep it between you and the client.

Rules that still apply

Electronic signatures are recognized for most agreements in the United States (the ESIGN Act and UETA) and the European Union (eIDAS). Some documents, such as wills or certain notarized deeds, have special rules in many places: check yours. Signing electronically doesn't change the other rules a job contract follows. In the United States, two examples:

• Notices a law requires in writing. Where a law requires information to be given to a consumer in writing, ESIGN lets you give it electronically only if the consumer has affirmatively consented, after receiving the disclosures it lists, and consented electronically in a way that shows they can access the information (15 U.S.C. 7001(c)(1)).
• Sales made at the buyer's home. The FTC's Cooling-Off Rule covers many sales of $25 or more made at the buyer's residence, with exceptions. For those, the seller must give the buyer a copy of the contract stating that they may cancel before midnight of the third business day, and a notice of cancellation form (16 CFR 429.0 and 429.1).

Check the rules where you work. This is general information, not legal advice; see electronic signatures in the United States for the federal rules.

What it costs

A contractor who sends 10 estimates and 6 change orders in a month uses 16 documents. That fits the Signing plan, $5 a month for 20 documents. Your first 2 documents are free, in total, your clients never pay, and you can cancel any time.

Service (as published October 11, 2026)	Monthly billing	Allowance
Attest, Signing plan	$5 a month	20 documents a month
Zoho Sign Standard	$12 per user a month ($10 per user billed annually)	25 envelopes per user a month
DocuSign Personal	$15 a month ($11 a month on an annual commitment)	5 envelopes a month
Dropbox Sign Essentials	$20 a month ($15 a month billed yearly)	Unlimited signature requests, 1 user

At 16 documents a month, DocuSign Personal's 5 envelopes wouldn't cover the job. On Attest, a document voided before anyone signs, or a draft you discard, is given back to your allowance.