To disable the welcome screen in IntelliJ IDEA, follow these steps:
From the main menu, go to File > Settings (on macOS, go to IntelliJ IDEA > Preferences).
In the Settings window, expand the Appearance & Behavior section and click the System Settings option.
In the System Settings section, uncheck the "Show Welcome screen" option.
Click the Apply button to save the changes.
After these steps, the welcome screen will no longer be displayed when you start IntelliJ IDEA.
Note that these steps may vary slightly depending on the version of IntelliJ IDEA you are using.
For more information on customizing IntelliJ IDEA, you can refer to the IntelliJ IDEA documentation.