what is a force restart affects

A forced-restart simply “forces” a restart of the device without opportunity of saving running data. To be clear, only un-saved data (associated with running Apps) may be lost.

After restart, any previously running Apps will automatically resume from the last saved-state. Apps that were force-closed prior to the restart will remain closed. Apps that are manually restarted will re-initialise.

In summary, a forced-restart runs a small risk of losing unsaved data. Given that iPadOS is regularly saving running state-data, the risk of data loss is low.

Unlike a forced-restart, which is immediate, a regular restart or shut-down will save the running state of all Apps and data prior to performing the commanded action.

All it will do is close all of the apps you had open, and restart the device. No data will be lost.