Yes in general the main stations in big cities have places to store your luggage. But it is different from station to station or country. 

There are few pages and apps that offer luggage storrage in small stores across the Cities usually one or two are near the train station :)

Luggage storrage on popular stations (destinations) can be quite full. For example the luggage storrage in Split (Croatia) is in summer always full :D

Also-before covid, in AMSterdam-even before 8.00 mornings.

Note that-to the utter surprise of many a young person, many of these boxes want exact change in coins. Often there are S/M/L boxes with different prices. But otherwise others only want payment by card. And-also to the utter surprise of some, in quite a few there may still be a manual window with real working persons.