Under normal circumstances, you will invoice your clients at the end of each month and you will add VAT at the standard rate, but you should be aware that there are VAT rules governing the issue of invoices. The time of supply of your services is known as the tax point, and you must account for VAT in the tax period in which the tax point occurs, at the rate in force at that time. However, when you supply services on a continuous basis and receive regular payment upon presentation of invoices, the tax point is the date of your invoice, but when you finish your contract you must issue your invoice within 14 days of completing the work. Also, you should note that if you ever receive payment before you have issued an invoice, the tax point becomes the date you received payment and you must issue an invoice within 30 days of this date. In such a case the tax point date and the date of issuing the invoice must both be included on the invoice and you must account for VAT in the tax period in which the tax point occurs.
To issue a VAT invoice you must send or give it to your client to keep. A tax point cannot be created simply by preparing an invoice, and you may not delay accounting for VAT until you have received payment. We recommend that you issue fee invoices immediately after the end of each month, and that you date them the first day of the month following the month to which they relate. This means that if you invoice monthly you will have approximately 9 weeks to collect payment of the last invoice in each quarter before you need to account for the VAT to HMRC (e.g. the VAT on your invoice for work done in February, dated 1 March is due by 7 May).
You may not usually be in a position to submit invoices for your expenses quite so early, and we suggest you arrange to submit separate invoices for expenses later in the month, when you have gathered together all the information you need. The first or last invoices relating to a contract may cover a period of longer than one month, but you should avoid issuing invoices that bridge different accounting years, be it your accounting year or your client's accounting year.
If you are using Competex FreeAgent you can create your sales invoices directly from the software and there are a number of templates available.