In order to be able to change templates and text blocks, the DocuBuilder template manager has to be installed and the user has to have the rights to make changes to these.
For further installation, see: https://documizers.atlassian.net/l/c/PAXVKbNY Installation or Upgrade of DocuBuilder Template Manager

For further extended possibilities see the separate Knowledge Base for template management. https://documizers.atlassian.net/l/c/ZKZgeACJ DocuBuilder - Manage Templates and Text Blocks