Where a property is on the market and potential purchasers view it, get schedules, and make enquiries, one interested party may be quicker than others about taking things forward. If so, they may phone to make a Note of Interest in the property. This is a marker laid down with the estate agent that the party wishes to be involved if there is a closing date. The estate agent should then not fix a closing date nor accept any other offer without allowing the party who has made the Note of Interest to make their own competing offer.
When someone is interested in buying your property they will instruct their solicitor to make a written offer. This can be subject to survey or to inspection of the Home Report, but will usually specify the price they are willing to pay, the date of entry (completion), and a list of fixtures and fittings they would like to purchase, as well additional legal clauses there to protect them.
If there are multiple notes of interest then a closing date will be set by your estate agent under instruction from you to give all parties the chance to make a formal legal offer through their solicitor, and the offers are all submitted to the estate agent in time for that deadline (it is usually midday).
You are not duty bound to accept the highest or any particular offer but can choose which offer to accept under your own free choice. It is bad practice for an estate agent to allow an offer to be accepted when there are already notes of interest made by other parties. Unsuccessful bidders are not entitled to know the details of the successful offer.
Once someone has decided they like the property, they will instruct their solicitor to make a written offer. This can be subject to survey or to inspection of Home Report, but will usually specify the price they are willing to pay, the date of entry (completion), and a list of fixtures and fittings they'd like to buy.
Your solicitor will receive the offer directly or via your estate agent, go over its terms with you, and send the purchasing solicitor a written qualified acceptance. This accepts the price etc (assuming it is acceptable) but qualifies the list of purchaser's legal clauses by deleting some or amending some, and adding in additional clauses to protect you.
The purchasing solicitor then goes over the qualified acceptance with his client and either replies in writing to your solicitor accepting their qualification clauses, and makes the contract binding between the parties, or sends a further missive back to your solicitor challenging some of his clauses.
This process, which can be of variable length and number of formal missive letters between the solicitors, ends with you and the purchaser having agreed all legal terms, and being in a binding contract, which neither can escape from without the consent of the other, or without legal/financial penalty consequences.