This depends on a number of different factors; what pill you take, how many pills you’ve missed and where in your packet you are.
Take a pill and then take your next once at the usual time, taking two on the same day is fine. Carry on taking your pills as normal but use condoms for a week as you won’t be protected against pregnancy.
If you have only missed one pill, take that pill when you remember and finish the pack as normal. You will be protected against pregnancy
If two or more are missed, take your most recent pill when you remember and finish the pack as normal. You will not be protected against pregnancy and will need to use condoms for a week.
Emergency contraception may be needed if there has been unprotected sex around this time. This is available from GUM clinic up to five days after unprotected sex. If you are towards the end of your packet (less than seven pill), it needs finishing and then start the next packet without having the seven day break.
Pills missed anywhere else in the packet (more than seven pills left) take pills as normal with a seven day break.