The Teaching of the Church is that one must confess mortal sins in kind and number.
As to venial sins one need not confess them at all - let alone give a number (though it can be good at times say for the non-scrupulous to take a serious look at a particular venial sin -at the number --etc).
It is though very recommended to confess venial sins - at least some of them - frequently.
1458 Without being strictly necessary, confession of everyday faults (venial sins) is nevertheless strongly recommended by the Church. Indeed the regular confession of our venial sins helps us form our conscience, fight against evil tendencies, let ourselves be healed by Christ and progress in the life of the Spirit. By receiving more frequently through this sacrament the gift of the Father’s mercy, we are spurred to be merciful as he is merciful scborromeo.org/ccc/ccc_toc.htm
Venial sins can be forgiven in many many ways…prayer, act of love, act of contrition, reading Sacred Scripture even contributes to their forgiveness, reception of Holy Communion, the prayerful use of holy water etc etc
And of course in confession in a specific as well as general way.
Saint Augustine noted that we pray the Our Father for forgiveness of our daily venial sins…