How to setup an old (2013) HP Pavilion model #S5-1204 for video-conferencing.

[REMJR1]

What are my options for setting up for video-conferencing (Zoom?) on an old HP Pavilion Slimline s5-1200 Desktop PC series [Warranty ended on February 17, 2013]?   The PC was upgraded from Windows 7 to Windows 10 in June 2020.  The PC has at least one open USB port.  The home has internet connectivity.  Do I just need a "web-cam" connected to the USB port?  Isn't a microphone also need?  Is one build into a web-cam or does a mic need to be purchased separately and plugged into the audio jack?  How about hearing the audio from a conference call?  Would audio be played through the PC's internal speakers?  Anything else I should be asking/answering regarding getting a computer setup for my 94 year old mother so we can video-conference with her?

[Prométhée]

Hello
I will answer you simply, in theory, because never used this type of function
But what I can tell you, preferably a quality USB webcam will suffice, except for mistakes they all have a microphone!
you can use the computer speakers ( speakers for computers, I understand that you are talking about internal speaker, if that's not it on a tower!) , to hear what is being said, but a headset might do the trick.