html/php4 program vs code

I have another question. First I would like to explain a few things. I live in the middle of nowhere. My nearest gallon of milk is 15 miles. The nearest city is 65 and the college is further. I do not drive. My husband is a DOT employee and we live on a modest income. I am the grandmother of five. We purchased my computer almost a year ago with our tax refund. My computer has been a wonderful learning adventure and I do want to continue to learn. I offer this explanation as a reason for my lack of knowledge and computer ignorance.

Now, on with the questions…I want to make sure I understand something about php4. I think it is programming, meaning code, I can write into html. Is this correct? If so then it is not a “program” I download, correct?

In advance I appreciate the help of anyone who would consider answering my question. I do have more, but do not desire to be pushy.

Thank You, Persever

php4 / php is a programming language.
however it does require a "program" running on your webserver for it to work.

php is a language like HTML.

however HTML merely presents and structures information on a page (front-end, client-side), PHP can connect to databases and perform many jobs BEFORE the result is seen in HTML, this is called (back-end / server-side).

Thank you for your help.