Sra. ___________ Señora (that means she is married)
Srta. ___________Señorita (she is not married)
If you don’t know Sra. if you know she is young Srta.
Sr. __________ Señor (Always señor for guys)
These abbreviations can be used in 1, 2 and 3 in this graphic showed above in the link Spanish formal letter
Read the folowing with the Spanish formal letter graphic on the link please…so that you can understand what I am talking below.
In number 1 you don’t have to, you just can put the name like in the example or Srta. Margarita Perez
In number 2 you don’t have to as well, but in this case we decided to write Srta. Mara Bogado Poisson
In numer 3, at the salutation you can write