Indirect/direct object

Question

You need to send it to them. Se la necesitas enviar a ellos.

what is the function of ''se'' in the second sentence ?

Answer 1

It takes the place of les, the indirect object pronoun that is being clarified by the prepositional phrase a ellos.

When two 3rd person i.o.p. and d.o.p. occur together the i.o.p. is replaced with "se".

It is another one of those phonetic rules because le lo, le la, les lo etc. are easy to run together speaking or hard to distinguish when listening.

If not for that rule, your sentence would be "Les la necesitas...."

From this article:

Whenever both pronouns begin with the letter "l" change the first pronoun to "se."

• le lo = se lo
• le la = se la
• le los = se los
• le las = se las
• les lo = se lo
• les la = se la
• les los = se los
• les las = se las