Setting the cash basis in MTD
Most accounting in untied is on the cash basis where we "follow the money" and this is the HMRC default for individuals. If you have previously been on the accruals basis, this is how you set the cash basis in untied.
In MTD
On the Making Tax Digital tab, choose the tax year and then hit the cog against your self-employment income. Then change the dropdown under Accounting Type and Save. NOTE THAT THIS CAN ONLY CURRENTLY BE DONE AFTER THE END OF A TAX YEAR DUE TO HMRC SYSTEM RESTRICTIONS.
Not in MTD
The cash basis is the default (just don't tick the box to set the accruals basis in the self assessment form).