That depends on the type of the hp printer you have.
Some (primarily older makes) have a kind of a "ball" on the top side of the cartridge, which simply has to be stabbed into the cartridge, others have the ink hole covered by other means - just search for a way to get into the cartridge
I don't know if this applies to newer types as I only own older ones.
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Linux is like a wigwam:
No windows, no Gates, Apache inside.