Create a drop-down column - SharePoint List

SebastianSzyroki If you want to show/hide columns based on selection of option from choice column, you can use conditional formulas in SharePoint.

Let's say you created 3 columns: Category (choice column), TypeOfEquipment (Text), NameOfTraining (Text).

Then you can conditionally hide TypeOfEquipment and NameOfTraining fields from list form based on value of Category column.

Check this documentation: Specify conditional formula to show or hide columns 

Example, for TypeOfEquipment column, you can use formula like: 

=if([$Category] == 'IT Equipment', 'true', 'false')

Where Category is the internal name of your SharePoint choice column.

OR If you want TypeOfEquipment and NameOfTraining also of type choice columns, you can use Power Apps to customize list form and create cascading drop downs: 

1. Working with Cascading Lists in SharePoint and Power Apps 
2. Create dependent drop-down lists in a canvas app 

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