It depends on the phone firmware and Android version, but some will let you use an SD card as part of the internal storage pool.
https://www.howtogeek.com/242937/how-to-set-up-a-new-sd-card-in-android-for-extra-storage/
Android 6 Marshmallow or newer, and might find some manufacturers disable it as they like to mess around in weird and irritating ways with storage partitioning.
Use a decent SD card also. Reputable one that’s fast and known to be reliable (I find all microSD are flawed in some way and just die suddenly, but some last longer than others).
