Regular expressions can be used to find patterns in a string of text.

If I wanted to match for "Zeeshan" or "an", I could create a regular expression that looked like /Zeeshan/, and the word "Zeeshan" would be matched in my string.

When building a signup form, using a programming language that supports regular expressions, like JavaScript or Python, we can validate the password field by saying that it must be 8 characters long and contain numbers.