Learn Portuguese (Portugal): A rapariga pede a revista, e entrego-lha. - The girl asks for the magazine, and I hand it to her.

The word entrego-lha combines the verb entrego (I hand over) with the contracted pronoun -lha. This pronoun is a mash-up of the indirect object lhe (to her) and the direct object a (it, referring to the feminine word a revista). When you have both "to her" and "it" next to each other, they combine into -lha.

Why isn't there a word for "for" after pede?

The verb pedir means "to ask for" or "to request". The idea of "for" is already built into the verb itself, so you do not need to add an extra preposition like por or para after it.

Why is the pronoun attached to the end in entrego-lha instead of before the verb?

In European Portuguese, pronouns normally attach to the end of the verb with a hyphen in simple affirmative sentences. The word e (and) connecting the two phrases does not act as a "magnet" to pull the pronoun to the front, so it stays attached to the end of entrego.

How do we know it is "I" who hands over the magazine?

The ending of the verb tells us. Entrego is the "I" (eu) form of the verb entregar (to hand over or deliver). In Portuguese, the subject pronoun eu is usually dropped because the verb form already makes the subject perfectly clear.