Normally, submissions get acknowledged and allocated to reviewers (and maybe a sub editor) but the initial review can take several months. If you have not had an acknowledgement of receipt of your submission it is in order to ask for one.
I agree that several months is normative, and I appreciate the suggestion that it is appropriate to ask for clarification thereafter. I thought 6 months was an outlier.
It depends on the journal you are trying to publish. It could take from, let us say, 7 weeks to more than 6 months. Some journals are now making public their time schedule, which I believe is important to know.