You can submit your return either by post before the 31st October, or by 31st January if you’re filing online.
You can also submit your Self Assessment through the Making Tax Digital (MTD) scheme. This is currently not a requirement, but HMRC are moving towards digital submission for Self Assessment Tax Returns over the next few years.
Eventually this online system will replace the Self Assessment Tax Return, but at the moment it is a pilot scheme you can sign up to voluntarily.
Through MTD, you can use compatible accounting or bookkeeping software to keep records, and easily submit them to HMRC.
Using MTD can make it easier to keep track of your business expenses, tax and records.