Nowadays, it is not unusual for apps that have a capacity of more than 1 gigabyte, such as game apps. Most Android devices have a microSD card slot, so you can add storage by installing a microSD card, but if you just attach a microSD card you can use it for storing photos / videos and music Will not be installed.
However, if your device is Android 6.0 or later, you can substantially increase the storage capacity by formatting the microSD card as “system memory”. Not all devices support this feature and may be turned off intentionally by the manufacturer's policy, but it may be worth trying.
For devices that support “Format as internal memory”, open the screen in the order of “Settings” → “Storage” and select a microSD card, and in addition to the normal format (initialize the microSD card), select “Format as internal memory” Item is displayed. When you tap this, the microSD card will be initialized, and when completed, it will be available as a storage location for the app as well as the internal storage.
By the way, when using a microSD card as the main memory, be careful with the basic performance of the microSD card. Recent microSD cards have a standard called "Application Performance Class" that identifies the read / write performance (random access performance) required to launch and save applications, and can be easily understood at a glance.
As of January 2020, two types of application performance classes are defined, "A1" and "A2", and A2 can launch applications faster than A1 and A1 than cards without engraving. If you don't want to feel stress when launching the app, it's safer to choose a microSD card marked "A1" or "A2".