The micro-entity accounts filing process allows the option to produce the accounts in .html form. This is the format needed to attach to your Corporation Tax Return (CT600) when filing with HMRC via commercial tax software.

Note: HMRC's free joint-filing service (CATO) closed on 31 March 2026, so a CT600 can no longer be filed directly through HMRC's own portal. Commercial third-party tax software is now required, and this .html accounts file is what you attach within it.

The .html file will be saved in your Document Library which can be accessed at the top of the screen. It will be labelled with the company name and type of document, below is an example.

Please click the blue arrow under Actions on the right-hand side of the screen, this will open a pop-up box asking what Firefox should do with the file.

Select Save file to add it to your downloads file. This can be accessed on the browser as shown in the screenshot below, and in the folder which downloads appear on your PC.