There are two ways to do this:
Unconditional Offer: An unconditional offer is when you offer an amount to buy the house as listed (with or without drapes, fixtures, etc) without adding or negotiating any other conditions.
Conditional Offer: A conditional offer is when you offer to buy the property only if the vendor accepts certain conditions. These must be listed on the Offer to Purchase.
For example, your offer may be conditional on arranging finance. . If finance cannot be arranged within a certain period of time, the offer becomes void. For your own protection, you should nominate a specific lender as your source of finance. Leaving out a nominated lender or having open- ended finance conditions on your Offer to Purchase may force you to take up finance at substantially higher rates, perhaps shorter terms, and from a lender you would not prefer to deal with.
Another condition might be an extension of the settlement period. If the seller does not accept the conditions, further negotiation may take place or the offer may simply be declined.