If you were a partner in a partnership, the partnership sends you a T5013. It reports the amounts the partnership allocated to you, so that your share can be carried onto your own return.
You do not prepare it. The partnership does, and you use it when you file.
What it reports
The T5013, Statement of Partnership Income, reports the amounts a partnership allocated to you as a partner. For a partner who is an individual, amounts shown on this slip have to be reported on an Income Tax and Benefit Return.
Who sends it
The partnership itself.
The instruction sheet is part of the slip
This is the unusual thing about the T5013, and the reason this article is short. The Canada Revenue Agency (CRA) page for the slip does not explain the boxes. Instead it tells you to follow the instructions on information sheet T5013-INST, Statement of Partnership Income – Instructions for Recipient, which should be included by the partnership with the information slip.
So the box meanings live on the instruction sheet, not on the CRA's slip page and not in this article. If your slip arrived without T5013-INST, ask the partnership for it before you work through the boxes.
The page does point to one line by name: Line 12200 – Net partnership income (limited or non-active partners only).
If a slip is late or looks wrong
The partnership issued the slip and is the one to ask about it, and the one who can supply a missing instruction sheet. The CRA page this article is written from does not state a date by which the slip has to reach you.
What to keep
Keep the slip and the T5013-INST information sheet together. Separated, the slip is a column of numbers with no key.
Keep anything else the partnership sends alongside them, such as a covering statement or footnotes, since the instruction sheet is written to be read against your own slip.
Dossier stores the slip and identifies it as a T5013, so it is with the rest of your year's paper. It does not read the amounts off it, and it does not interpret the boxes; the instruction sheet from the partnership does that.
Official CRA sources
Source: Canada Revenue Agency (canada.ca). Not tax advice.