CoQ10 comes in two primary forms: ubiquinone and ubiquinol.
Ubiquinol is the reduced, active antioxidant form of CoQ10 and is more easily absorbed by the body.
However, ubiquinol tends to be more expensive.
Ubiquinone is the oxidized form and is generally less expensive but might require a longer period to show effects since the body must convert it to ubiquinol.
If you're older or have specific health conditions that impair CoQ10 absorption, ubiquinol may be a better option.
Otherwise, ubiquinone could suffice for general health needs.