Which “assign” are you asking for?

1. Those radio buttons = “I already handwrote the checks and just want to enter which #s I used”

Or:

2. “I will be printing this from QB.” Printing later, from QB, will then give you a pop up where you confirm or assign the first check […]

Resolution for 'bills mode issue: 'when paying bills I can not enter the cheque number in the pay bills mode?' available: Yes.

The bills mode issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the bills mode issue yourself by looking for a resolution described in the article. If it is a complex bills mode issue or you are unable to solve the issue, you may contact us by clicking here or by using other bills mode support options.

For more information about resolving issues related to bills mode in Quickbooks/QBO or to get support for the issue 'when paying bills I can not enter the cheque number in the pay bills mode?', click the link below: