***whats the procedure if u declare online undeclared income up to 4 years back?

[super1]

anyone knows how it works and whats the procedure when u declare undeclared income back? I read there is an option to do it online nad you can declare it up to 4 years back. How it works, what are the procedures, penalties and how do they react and check it? thanks

[bd6759]

https://www.gov.uk/government/publications/hmrc-your-guide-to-making-a-disclosure