An offer to purchase is a document signed between the seller and buyer to confirm the conditions that must be fulfilled before a home sale can go ahead.
Both the buyer and seller will want to include conditions and clauses that protect their interests.
For example, the buyer can include a requirement for a home inspection.
Failure to fulfill the conditions by either party renders the offer to purchase null and void.
It is a legally binding document and withdrawing from it may incur penalties unless you are doing so because a condition listed in the document was not met.