i get this macos wants to make changes and not sure what to do

I know. If you have Skype installed, then most likely the Skype app was just recently updated. When the app was updated its settings and permissions may need to be reset which is what macOS is telling you by popping up this message to authenticate to all Skype access to the Keychain. A part of Skye may always be running in the background even if the app itself is closed. It is this background part of Skype that is triggering macOS to prompt you for permission to make changes to your system.

I'm only guessing this is a legitimate request from Skype since I don't use Skype and cannot be 100% certain this icon is definitely for Skype (very poor security implementation as there is not enough details to understand what app and the exact reason for the request). Unless another contributor chimes in here to offer an opinion you may need to contact Microsoft to confirm if this would be a legitimate request if you have doubts about its authenticity. Maybe official Apple Support can confirm, but most likely you will need to contact Microsoft if you have doubts.

It looks like Skype wants to make the changes (at least it looks like the Skype app symbol). I agree it is unfortunate that macOS doesn't explicitly state what app is asking for permission or why specifically it wants or needs to make the changes. Assuming that you have Skype installed.

Until you supply your username and password this will keep popping up. Probably a Skype app update has triggered a need to gain permission for Skype to access your Keychain. Like I said Apple's security model could use some work because a person cannot tell what apps this is for and why this permission needs to be granted. I've seen similarly vague requests on our organization's Macs where I'm not familiar with some of the app icons. I have the same complaint on my iPhone as well.

If you have Skype installed, then it seems you have no choice but to provide permission or uninstall Skype, unless there is a Skype preference you can change so Skype doesn't need access to your Keychain. You may need to contact Microsoft for assistance.