The most common interval for filling out and submitting a VAT return to HMRC is quarterly. Sometimes a VAT period can be yearly or monthly. If you use the annual accounting scheme, you only need to file one VAT return each year, but you must make interim VAT instalments on account, based on an estimated liability for the year.
You can ask HMRC for a monthly tax period if you expect to regularly reclaim VAT (if you usually pay more VAT on your purchases than you charge on your sales). In that case, you will have to file 12 VAT returns per year.
You can't use monthly VAT periods if your turnover is below the VAT threshold and you registered voluntarily for VAT. You must file a VAT return even if you don't buy or sell anything VATable during your VAT period.