When you do something that takes time (repairing, searching, crafting, using an item) a gold bar appears at the bottom of the screen with what you are doing and how far along it is.

• Press X to cancel (you can change the key in GTA Settings > Key Bindings > FiveM). Some actions can't be cancelled.
• Dying or going down cancels it.
• While the bar runs you may not be able to move, drive or shoot, depending on the action, and your inventory stays closed.
• A cancelled action turns red and shows "Cancelled"; nothing is used up or given.