Say and tell have similar meanings, but they are used in different ways.
Tell is used only to instruct or inform, and when the receiver of the information is included as an object of the verb.
Tell means “to give information to a person”, is always followed by a person. (Dar información a una persona”, siempre es seguido por la persona que recibe esta información).
tell (present) and told (past).
- Has she told you the good news, yet?
- Please tell us your name and occupation.
- Can you tell me what happened?
- Don’t worry, I won’t tell anyone your secret.
Say is used when the receiver isn’t mentioned in the sentence:
say (present) or said (past).
- “Good morning,” said the woman behind the counter.
- I said three words before he interrupted me again.
- Harry says she doesn’t like chocolate.
- She said that the new website design was great.
Don’t make this common mistake!
- He said me that he had to leave. X (wrong)
- He told me that he had to leave. ✓
Here we talk about some difference in meaning, but there are other uses of both of these verbs.