About upgrading onboard(fixed) ssd and rams on Macbook Models

Hello everyone, I have some questions about upgrading ssd and rams which are onboard and fixed.

I have been searching and watching some videos too about this subject. And saw some videos which says when you upgrade your onboard ssd, lets say from 128GB to 512GB you need to programme the new voltages of these SSDs to the bios. Is this right? And I heard that it is same for Rams too.

And my other questions is how do we choose the right ones to the model? Where can we find them to buy?

If you have any details about these. Will be glad to discuss it under this post.

Thank you