According to the Gold Book and IUPAC 1988 Recommendations (Ref.1):
Hydron: The general name for the cation $\ce{H+}$; the species $\ce{H-}$ is the hydride anion and $\ce{H}$ is the hydro group. These are general names to be used without regard to the nuclear mass of the hydrogen entity, either for hydrogen in its natural abundance or where it is not desired to distinguish between the isotopes.
Thus, the following names comprise general names, to be used without regard to the nuclear mass of the hydrogen entity, either for hydrogen in its natural abundance or where it is not desired to distinguish between the isotopes:
- The atom, $\ce{H}$: hydrogen
- The cation, $\ce{H+}$: hydron
- The anion, $\ce{H-}$: hydride
- The group, $\ce{-H}$: hydro
The specific names pertaining to specific isotope of the forth category (hydro) are protio for $\ce{^1H}$, deuterio for $\ce{^2H}$, and tritio for $\ce{^3H}$ (Ref.1).
In IUPAC nomenclature, R-3.1.2 states that:
If the name of the parent hydride implies the presence of the maximum number of noncumulative double bonds (see R-2.4.1), other states of hydrogenation can usually be indicated by use of the prefix "hydro-" together with an appropriate numerical prefix signifying the addition of hydrogen atoms. This operation is regarded as the reduction of double bonds; thus, hydrogen atoms can only be added in pairs (by use of "dihydro-", "tetrahydro-", etc.). "Indicated hydrogen" (see R-1.3) is included if required by the parent hydride.
R-1.3 Indicated Hydrogen: Under certain circumstances it is necessary to indicate in the name of a ring, or ring system, containing the maximum number of noncumulative double bonds, one or more positions where no multiple bond is attached. This is done by specifying the presence of an "extra" hydrogen atom at such positions by citation of the appropriate numerical locant followed by an italicized capital $H$.
Some examples for these rules are given below:

References:
- J. F. Bunnett and R. A. Y. Jones, "Names for hydrogen atoms, ions, and groups, and for reactions involving them (Recommendations 1988)," Pure & Appl. Chem. 1988, 60(7), 1115-1116 (DOI: https://doi.org/10.1351/pac198860071115).