This is painful. Consider using Microsoft Office or switching careers. If you need to write < 20 letters consider doing it manually.
So you didn't listen and here it comes:
.ods
spreadsheet (.xls
, .xlsx
, .ods
). Use any columns that work for you, but be consistent. I like to use one column for the address, one column for the salutation line.If Writer keeps crashing on the last step, recreate your letter template from a blank page like a wild animal. Be careful to paste text without formatting or styles.