Voluntary Mitzva Performance I

May a woman perform mitzvot voluntarily? The test case is  semicha (Wikipedia)Smicha or semikhah (Hebrew: .mw-parser-output .script-hebrew,.mw-parser-output .script-Hebr{font-size:1.15em;font-family:"Ezra SIL","Ezra SIL SR","Keter Aram Tsova","Taamey Ashkenaz","Taamey David CLM","Taamey Frank CLM","Frank Ruehl CLM","Keter YG","Shofar","David CLM","Hadasim CLM","Simple CLM","Nachlieli","SBL BibLit","SBL Hebrew",Cardo,Alef,"Noto Serif Hebrew","Noto Sans Hebrew","David Libre",David,"Times New Roman",Gisha,Arial,FreeSerif,FreeSans}סמיכה‬, "leaning [of the hands]"), also smichut (סמיכות‬, "ordination"), smicha lerabbanut (סמיכה לרבנות‬, "rabbinical ordination"), or smicha lehazzanut (סמיכה לחזנות‬, "cantorial ordination"), is derived from a Hebrew word which means to "rely on" or "to be authorized". ">semicha, leaning on a sacrifice, a ritual from which women are exempt. We;ll also discuss the halachic meaning of voluntary performance, whether it can become like obligation, and whether voluntary mitzva performance is encouraged.