is it ok to say "we'll come on the dates between 18.4.19 till 23.4.19"

[AngryNathan]

or should I say "in the dated". can I say both ?

thank you very much for any help .

[Joe]

"in the dated" is not English.

Your first idea is better, but it should be:

We'll come on the dates between 18.4.19 AND 23.4.19.

That means you'll come 19, 20, 21, 22, but NOT 18 and NOT 23 because you said BETWEEN.

So maybe you really mean:

We'll come on the dates FROM 18.4.19 TO 23.4.19.

As usual, it all depends what you really mean.