Typing the same letter forty times with a different name at the top is how mistakes get made. Somebody gets Mr Naidoo's salary in Ms Botha's offer letter, and now you have two problems.
A mail merge fixes that. You write the document once as a template, put the details that change into a spreadsheet, and the merge makes one finished document per row. Done properly, it's faster and more accurate than doing it by hand. Done carelessly, it makes forty wrong documents in the time it used to take to make one.
Get the spreadsheet right first
Nearly every bad merge is a spreadsheet problem, not a template problem.
Give every column a clear heading, and name the columns the same way the template names its fields. If the template says client.name, call the column client.name, not "Client" in one file and "Customer Name" in the next. Matching names means the columns line up with the fields on their own, and you're not mapping them by hand every month.
Keep one row per document, with no blank rows in the middle, no subtotals at the bottom and no notes typed into a spare cell. The merge reads every row as a person. A row that says "check with Thabo" becomes a letter addressed to nobody.
Watch the leading zeros. Excel treats ID numbers, account numbers and phone numbers as numbers and quietly drops the zero in front. Format those columns as text before you fill them in. Fixing them after the zero is gone means retyping them.
Check how amounts and dates come out
A spreadsheet cell can hold 16100 and display R16 100,00. The merge may see the first one. Before you run a batch, merge a single row and look at how the amounts and dates come out. If they're wrong, fix the format once, in the template or the column, rather than correcting the documents afterwards.
Check one, then run the lot
Run a single row and read the document all the way through, the way the recipient will. Check the name, the amount, the date and anything that should appear only for some people. Then run the whole batch.
It's tempting to skip this step when the template hasn't changed. Run it anyway. The template is usually fine. It's this month's spreadsheet that has the new column someone added in the middle.
Decide how the documents go out
You can download the finished documents and send them yourself, or have each one emailed straight to its recipient. Emailing from the merge saves an afternoon of attaching files, but only if every row has an email address. Check that before you start, not after the first twenty have gone.
Write the email like a person wrote it. "Your offer letter, Sipho" gets opened. "Document attached" waits until Monday.
Where mail merge isn't the right tool
A spreadsheet row is flat: one name, one amount, one date. If the document needs a table with a line per item, like a quote with twelve line items, one row can't carry that. Fill those documents from your own system instead of a spreadsheet.
How it works in E·BIZI Papers
In E·BIZI Papers you drop a CSV or Excel file onto a template. Papers matches the columns to the template's fields and makes one document per row, up to 500 rows in a batch. Download them all as a ZIP, or email each one with your own subject and message. Fields like {{Name}} work in both, so every email greets the right person. A password column puts a different PDF password on each person's document, which suits anything private, as long as the passwords kept their leading zeros.