Unfortunately you will need to keep your receipts for up to 6 years depending on whether you are VAT registered. Any receipt (that you have claimed for), sales invoices and bank statements should be retained as HMRC can request to see these up to 6 years.
Thankfully, you are able to keep all archived receipts in electronic format rather than in paper form. Therefore, if you prefer to scan in all documents and keep them on your computer this is fine. Just ensure you keep a back up somewhere!