An outsourcing proposal usually has a price on the first page and a responsibility matrix near the back. Read the matrix first: it says who does each piece of work and who signs it off once the contract starts.
Check three things. Every line should have exactly one person who signs it off. Decisions about money, people and suppliers should stay on your side. And every line where the firm does the work should have a service level that says how fast and how well.
If a line is vague, such as “support with month end”, ask for it to be split until each part has a name next to it. That is where most disagreements in the first year begin.