sharing preprint using the journal's template?
If a journal allows authors to post their pre-prints, the general rule—although it is by no means absolute—is that you may use the manuscript in the form in which it was submitted to the journal, but you cannot use the version created by the journal's production staff.

However, you should consult the specific policies of the journal to see exactly what is or is not allowed, as not all journals allow preprints.