I have Apple ID password, Computer account password. But what is Mac Password?

I got a notification that a program update is available.

That sounds fishy; all the more so given what happened after that.

I strongly recommend that you change your Apple ID password, right now.

Update your Apple ID password - Apple Support

Do it now.

Never supply confidential information just because something asks you to divulge it. A request for your Apple ID credentials should never come as a surprise.

rasa260 wrote:

I have never questioned the need for safety, of course safety comes first.

But if you get a pop-up window that says enter Mac Password, without any explanation, what was meant by that or Apple ID password, computer password, but maybe some third new password.

You close the window.

That's the way to put feel-good words such as "safety comes first" to actual use.

This isn't an Apple thing. It's just common sense. Read Effective defenses against malware and other threats - Apple Community.

I have not given anything to anyone.

Very well, but that statement conflicts with your earlier statements:

When I entered my Apple ID, then they asked me to enter my Mac Password.

I re-entered the Apple ID password, the computer password.

My question was, is the Mac password the same as the Apple ID password, the computer account password, or is it something else.

They can be identical, if you choose them to be. They are not strictly related to one another, but your Apple ID password can be used to reset your Mac's User Account password, which is the reason I recommend you change it first.

And I'm not the only one who has a question about the Mac password. The Internet is full of such questions.

Good to know. I thought perhaps you were the only one.

Unfortunately these days data theft has become commonplace. Any unexpected solicitation for your Apple ID, your Mac's password, your Windows password, your social security number / phone number / credit card number / birthing person's maiden name etc should elicit strong negative reactions from you.

Yes passwords are trouble, but you will not circumvent the need for password security by buying something other than Apple.