Hi Artistmama, here is the answer to your question with several examples so that you can understand well:
☆☆ The Personal "a" ____________________
✔ In Spanish, when the direct object is a person, it is preceded by the preposition "a". This word has no English translation. From the perspective of the English speaker, the personal "a" appears to be an extra word. From the perspective of the Spanish speaker, the personal "a" is required, and to not use it is a serious error.
→ Jorge llama a María.
✔ The personal "a" may also be used if the direct object is a domesticated animal, especially a pet, provided that the speaker attaches some sort of personal feelings towards the animal.
→ La mujer acaricia a su perro (The woman pets her dog).
→ El perro persigue a la gata (The dog chases the cat).
✔ The personal "a" is not used when the direct object is not a person or is an animal for which no personal feelings are felt.
→ Bebo la leche (I drink the milk) → milk is neither a person nor an animal
→ Miro la jirafa (I look at the giraffe) → no personal feelings are felt towards the giraffe
✔ The personal "a" is not used after the verb tener, or the verb form hay. This is true even if the direct object is a person.
→ Tengo dos hermanos (I have two brothers).
→ Hay cinco chicas (There are five girls).
✔ If the direct object is an indefinite person, the personal "a" is not used. The result is that the person becomes "depersonalized".
→ Necesito un médico (I need [any] doctor).
→ Necesito un jardinero (I need [any] gardener)
Because this Spanish grammatical structure has no equivalent in English, it is normal to expect that the students will forget to use it until a pattern of use has been established.
I sincerely hope this helps you, Artistmama. Kind regards.