How do I enter my websites and passwords into keychain?

If you go to Settings>Passwords & Accounts>Website & App Passwords then tap the + symbol at the top, there you can add website password information

Are you meaning to import a list you have elsewhere? The best method to add items, is to go to each website on your phone vs typing in everything manually. It should ask you to save the password information when you login

I keep receiving a popup screen from Microsoft Excel and a couple other MS apps asking to use my confidential information stored on my keychain. A few of questions: 1. this only happens on MS apps and I cannot get rid of the popup screen even if I "Deny" access?. 2. If this is it a legit request and if so how do I change my keychain password? Haven't a clue what it is, I know I established one years ago and many Macs have passed through my hands with this ever being a problem. #. If I change my password will it affect my other linked Apple products iphone, ipad, etc.

No. It has to be done one at a time.

I followed your instructions but after filling out the onfo I could not go further. I would not let me enter the password etc..

You can't enter the password for the website? You were able to enter the website name and username but can't enter the password?

I made a mistake. I did not give a complete website name. Thanks