Answer five questions about the supply and customer. You will get a practical indication of which invoice treatment to check.
If the reverse charge applies, show the VAT rate or amount and say the customer accounts for VAT. Do not add that VAT to the cash due.
Read the worked reverse charge invoice example, including CIS and end-user cases.
Sendinvo shows reverse-charge wording and the VAT the contractor accounts for without adding it to what they pay you.