Mr [ˈmɪstəʳ]
abbreviation:noun
Messrs (plural)Mister Sr.; señor Mr Jones wants to see you el señor Jones quiere verte; yes, Mr Brown sí, señor Brown
Use the article with Sr./señor, Sra./señora, Srta./señorita when you are talking about someone rather than to them:
Mr Smith is not at home El Sr. Smith no está en casa
Mr and Mrs Crespo are on holiday Los Sres. (de) Crespo están de vacaciones
Have you seen Miss Barrios this morning? ¿Ha visto a la Srta. Barrios esta mañana?
The abbreviated form is more common than the full form in writing.
Don't use the article before Sr./señor, Sra./señora, Srta./señorita when addressing someone directly:
Good morning, Mrs Ramírez Buenos días, Sra. Ramírez
Mr López, there's a telephone call for you Sr. López, le llaman por teléfono
CapitalizationWrite the full forms señor, señora and señorita with a small "s", even when using them as titles:
Mr Smith is not at home El señor Smith no está en casa
He was talking with Mrs Williams Estaba hablando con la señora (de) Williams
Addressing correspondenceUse Sr. Don/Sra. Doña (Sr. D./Sra. Dña.) rather than Sr./Sra. when giving both forename and surname. Don't use the article:
Mr Bernardo García Sr. Don or Sr. D. Bernardo García
Mrs Teresa Álvarez Serrano Sra. Doña or Sra. Dña. Teresa Álvarez Serrano