Could you please post the model number of your computer.
If you are talking about the BIOS password which you need to boot the computer then you will have to call Dell tech support in your region and they can assist you. You will have to prove ownership of your system.
If you mean the Windows 10 password then the link below will offer that information.
-Forum Member since 2016 -I do not work for Dell -A user helping other users -If you like an answer please click on thumbs up -If a reply is a solution to your problem please click on Accept as Solution Gaming on a home built ASUS Z170K i5 6600 Real work on an Inspiron 15 5575