Salesforce merged data into document. Can’t get it without too many spaces ....

I am sending to digital signature a template that has merged data from Salesforce.

I can't get this merged document to look like a normal document, since all merged fields take too much space or too short, like the form fields will never have the required length to look good in the document. 
 
So I discovered I had to user withespaces in the text tags, like {{some_merged_field      }}

it looks awful. Any idea on how to make this document to look nice?🙏🙏Please help.

examples of text too short or too long to look nice 

Word Infinity locks shortened:

there is too many white spaces between Palavecino and 'autoriza"