To remove Documill Dynamo from your Salesforce, you can first remove all the components or files related to Documill Dynamo then uninstall the Documill Dynamo package in Setup. For more information on how to uninstall a package: Uninstalling a Package in Salesforce
1. Delete Documill Dynamo template files
Go to Files, delete all the Documill Dynamo templates you have created. Save a backup of templates if you want to reuse later.
3. Check Recycle Bin
Check your Recycle Bin to ensure all the template files and related components are completely removed.
4. Uninstall Package
Go to Setup -> quick search for Installed Package
Select Installed Package, click Uninstall next to Documill Dynamo package
Follow the step to uninstall. If your org still contain components related Documill Dynamo, the uninstallation will be interrupted. Click to the files or components mentioned in the error message, remove it and redo step 4.