If at signer's login, the signature request document is not displayed on the top screen, signature button may also not display.
In that case please check the following points.
Step 1 Whether the user who first received the e-mail of the signature request has correctly set the signer
Please confirm whether 【Contact person operation】 in the above link article is completed.
Step 2 Do you properly log in as a signer role user?
【How to confirm the role】
Please click the user name in the upper right, and check the role in the displayed user information page.
If you do not see the signature button after correctly operating the above two points, please contact support team.