The length of 'Sahil' is: 5
Full name: Sahil Dhaliya
Functions are reusable blocks of code that perform a task. PHP includes many built-in functions like strlen() that you can call anytime to solve common problems. You can also create your own user-defined functions to avoid repeating code. Functions can take inputs (parameters) and return outputs, making programs cleaner, easier to read, and easier to update.