Go to your customer list by clicking customer. There is a small box to the left where you can select a customer and a small box at the top to select all.  Select them.  Click batch actions and send your email.

Resolution for 'clicking customer issue: 'How to send mass email to all customers from Quickbooks' available: Yes.

The clicking customer 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 clicking customer issue yourself by looking for a resolution described in the article. If it is a complex clicking customer issue or you are unable to solve the issue, you may contact us by clicking here or by using other clicking customer support options.

For more information about resolving issues related to clicking customer in Quickbooks/QBO or to get support for the issue 'How to send mass email to all customers from Quickbooks', click the link below: