Thanks for your response. I can see how mailmerge would be useful here however I am also looking to populate the content of the document with different wording depending on the company. I have pre-defined text that can be inserted, looking for a way to select this text, for example.

Dear <NAME>,

I hope this letter finds you well.
<Pre-determinted Text #1>

I am therefore ask for your help in <Pre-determinted Text #2>

<Pre-determinted Text #3>
Yours hopefully
Miss L Smith