In Spanish, the preposition "a" precedes the direct object and goes after the verb which refers to people and sometimes animals.

Yo conozco a María.
I know Mary.

Because it is used before people, this is called the "personal a". We often use the personal a with:

People
Veo a Pablo todos los días.
I see Pablo every day.

Yo voy a ayudar a María.
I am going to help Mary.

Pets
Yo saco a mi perrito todos los días.
I take my puppy out every day.

Tú ves a los pájaros.
You see the birds.

Exceptions:

We don't use the personal a with the verbs tener, necesitar, buscar, and haber:

the verb tener
Tengo dos hijos.
I have two children.

forms of haber
En mi familia hay seis personas.
In my family there are six people.

non-specific things or people
Busco un trabajo facilito.
I'm looking for an easy job.