Daily PrEP is somewhat forgiving with missed doses, which is an advantage it has over condoms, which provide no protection when they are not used. From the write-up of a study on PrEP’s protection:
In terms of stopping PrEP, after 30 days of daily dosing, the estimated protection offered by the PrEP remaining in the body from HIV transmission via anal intercourse was 97% 24 hours after the time of the first missed dose, 96% after three days, 93% after five days, and was still 90% a week later. (Source from AidsMap)
However, studies only demonstrate that level of protection for cis men having anal sex. It is especially important for cis women and trans men to avoid missing doses of PrEP.
Your provider can help you strategize about ways to remember to take PrEP daily.
If you miss a dose of PrEP, continue with the next dose. Taking two doses to make up for a missed dose is unnecessary.