An XML signature is like a seal or a stamp that we put on a document to show that it is original and has not been changed by anyone. It is used to ensure that the document is secure and that it comes from a trusted source.
This seal contains information about who signed the document, when they signed it, and what the document contains. When someone receives the document, they can check this seal to make sure that it hasn't been tampered with and that it came from the person they think it came from.
Think of it like your parent signing your homework after you've finished it. The signature proves that your parent looked at it and approves of it. Similarly, an XML signature proves that the document is authentic and trustworthy.