The equation for a beta decay might be written in terms of atoms (and ions) as follows
$$\rm ^{14}_{\;6}C \to {}^{14}_{\;7}N^+ + {}^{\;\;0}_{-1}\beta^- + {}^{0}_{0}\bar \nu$$
A reason for doing this is that when evaluating the Q-value of such a decay the masses of atoms (and electrons) rather than nuclei are used.
That being the case it is important to keep tracks of both the constituents of the nuclei and the numbers of orbiting electrons.
$\rm N^+$ indicates that it is a single positively charged ion of nitrogen and together with the the negatively charged $\beta^-$ the right had side of the equation has a net zero charge commensurate with the neutral carbon atom on the right hand side.
That labeling also helps keep track of the numbers of electrons on the right hand side of the equation so that in terms of mass, the nitrogen ion and the beta can be assumed to have the mass of a nitrogen atom (assuming that the binding energy of the seventh electron in the nitrogen atom is very small compared with the nuclear binding energies).
The $-1$ label for the beta can be thought of as being useful in evaluating the number of protons in the resulting nitrogen nucleus.
This is done by saying that a beta minus emission results in an increase of one proton in the nucleus which in terms of an algebraic calculation can be written as $6=7+(-1)+0$.
That $-1$ label can be thought of as an aid to help "balance" a beta minus decay equation.
Think of the $-1$ label as a useful aid which by extension can be used to predict what happens when the label is $+1$ as in a ${}^{0}_{1}\beta^+$ decay?