The first thing I like to explain to a new client, is that a purchase, "the offer", becomes a "contract" once it accepted and signed by all parties. Therefore, it is very important to take some time to actually READ it and understand it PRIOR TO signing it!
Some real estate agents will fill out the form, slide it across the table, and ask you to "Sign here". They may also tell you that it is a "standard contract" used in all real estate transactions in your area. These statements are partly true, in that most purchase agreements that are approved by the state or local association of REALTORS® are standardized, but there are still many financial and negotiating decisions you, as a buyer, will need to decide while completing a purchase agreement. If it has been filled our for you, be sure to ask your agent to point out and explain everything that was filled in on your behalf. Not that they're being dishonest, but to ensure that you agree to all of the terms of the agreement.
Personally, when I work with new clients, especially first-time home buyers, I like to schedule a meeting with them, early on, just to go over the purchase agreement, the attached disclosures, and the basic process of making an offer. I definitely prefer to do this prior to them get serious about looking at homes with the intent to buy. Spending an hour or so going over the not-so-exciting paperwork, will allow us to focus on the details of the offer instead of them seeing it for the very first time when they are excited, nervous, and possibly under a short timeline.
The bottom line: If you are signing any contract, it's best that you first understand your legal obligation to which the contract is committing you!
Happy House Hunting :-)
The same applies to sellers who are signing a listing agreement and disclosures!