Publication and Subscriber Issue in Transaction Replication

i have a doubt in transactional replication, if i add a new artical in publication will that replicate in subscriber directly or not? if not, should i create new publication and subscriber ?
please clarify me this

You can add another article to an existing publication which will replicate to the subscribers. You just need to follow the steps here.

Never create a new publication that will have tables in it that are foreign keyed to tables in another publication. You don't want the data arriving in an incorrect order on the subscriber (child data exists but parent data doesn't).