Questions & Answers about zhè shì tā de zhàngfu.
Here 这 means this and stands by itself as a pronoun.
- 这是她的丈夫。 = This is her husband.
- 这个 often means this one or this + noun/classifier expression
You can hear 这个是... in speech, but 这是... is the most natural and standard way to introduce or identify someone.
是 is the verb to be in an identification sentence.
This sentence has the pattern:
- 这 = subject
- 是 = linking verb
- 她的丈夫 = noun phrase describing who he is
So 是 connects this person with her husband.
A useful note: Mandarin uses 是 for A is B type sentences, but not usually before adjectives.
- 他是老师。 = He is a teacher.
- 他很高。 = He is tall.
Not 他是高.