The first step is to find where your current Mortal Kombat XL save data is stored. The most common location is within your Steam directory. The PCGamingWiki, a reliable resource for PC game configurations, lists the path as:
Historically, NetherRealm Studios does not ban PC players for using 100% save files, as these files only unlock cosmetic variants, offline krypt items, and character access already present in the game code. However, use them at your own discretion when entering competitive ranked modes. Mortal Kombat Xl 100 Save Game Pc