Hi Shiva, The first sentence is grammatical, but I would say that “I’m free all day Tuesday before 7 pm” sounds clearer and more natural to me. Then the second sentence would be clearer as “If you have time for a visit sometime that day, let me know.”

thank you so much for this complete answer

When you are free is a little vague. Are you free only at certain times on Tuesday morning? Are you free Tuesday morning all the way up until 7pm in the evening? I would write it as one of these two: I'm free on Tuesday morning from ___ til ___, and in the afternoon from ___ til 7pm. If you have time to visit then, please let me know. OR I'm free on Tuesday until 7pm in the evening. If you have time to visit then, please let me know.