The grout and/or caulk in my shower tub has a few cracks and missing pieces. I can’t tell if the corner and the seam at the bathtub are caulk or grout (it feels rough like grout, but not sure). I don’t usually use this shower, but I am expecting a guest in a few weeks.

How do I fix these issues? Do they all need to be fixed before the shower can be used again?

Here’s what it looks like:

https://postimg.cc/gallery/Ygn89BN