Macros can be enabled automatically in several ways. The two easiest ways are:
- You can trust a folder containing the file where your macros are. Check File > Options > Trust Center > Trust Center Settings > Trusted Locations
- If you don't have rights to change this (because your IT guys don't trust you) then an alternative is to put the template into your User Templates folder location which is automatically trusted. By default, this folder is located in %appdata%\Microsoft\Templates

If you are sending files to external clients, then having them do something like this is very unlikely so you need to examine whether there is a non-macro alternative to what you are trying to achieve and whether its worth asking them to install templates to these trusted locations. I would be exploring whether a form with linked Content Controls might work better as a way of getting user inputs.

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Andrew Lockton
Chrysalis Design, Melbourne Australia