in metatrader 4 you can create a 38 minute chart if you want, but if i want this on metatrader 5,
how can i do it without offline charts?
Just to be clear: you will most likely need to do (quite a lot) of coding to make them work, unless you can find something that is already working.
No, I don't mean that necessarily.
Even "PeriodConverter" in MT4 is a script. It isn't an inbuilt feature of the platform (and it is somewhat limited).
Presumably there will be an equivalent to the PeriodConverter script in MT5 in the not too distant future, if not already.
It's not yet available with MT5.
Some people are proposing custom solution, see Market and Codebase.