A signature is like a special mark or drawing that you make on a piece of paper or a document to show that you agree to something or that you did it yourself. It is just like putting your name on a drawing that you made or writing your name on your homework to show that you did it. It is a way of showing people that you said or did something and that you stand by it.
Sometimes, grown-ups sign important papers like contracts or legal documents, and this is very important because the signature shows that they agree to what is written in the paper. It is just like saying "yes, I agree to do this" or "yes, I promise to do what is written here."
Signatures can also be digital, like a picture of your handwritten signature that you can put on documents online. This is helpful because you can sign things without having to be in the same room as the person you are giving the paper to. It is like drawing your name on a tablet or a computer instead of a piece of paper.
In summary, a signature is like a special mark or drawing that you make on a paper or a digital document to show that you agree to something. It can be used to sign important papers and legal documents to show that you promise to do what is written in the paper.