If you or your website admin has gotten an email that looks like this in recent days, here's why you should pay attention to it.
The Google Analytics Universal analytics product will be sunsetting on July 1, 2023. After that it will stop collecting new data, and you will have to use GA4, the next generation Analytics product.
"So what?" you ask. "I have a year before I need to worry about that!" No, you don't. Even if you don't intend to do anything with GA4 until you're forced to, you want to run it in parallel starting as soon as possible because you need it to start collecting historical data because the historical data from Universal Analyics will not transfer to GA4. So if you simply switch to GA4 a year from now it will have no historical data available for comparison. You need to start collecting data now.
There's no issue with running both at the same time for the time being, some sites have done this for years.
So don't delay to set this up to start collecting data, because starting July 1, you won't be able to do year over year comparisons for as long as you wait to get GA4 data collecting.