Not every medication is manufactured in the precise doses required. To get to the right amount, a few common doses will be produced with score marks to allow easy(ish) division for a smaller amount. For example, one of my family members has needed a half-pill of thyroid medicine. Something like a 75mcg pill split in half to make it 37.5mcg.

It’s very common in Ukraine for example. I take 80mg Valsartan. The pharmacy on the way home maybe only has 160mg. Fine I’ll buy the 160mg and split it. I could keep looking and find a pharmacy with 80mg in stock or plan ahead and order online but splitting the pills is no big deal.

Another comment mentions Metformin. This is more of a hassle since I find the 1g tablets awkward to split with my pill splitter due to the size, and yet for some reason finding the 500mg version is rare for me.