Small group where the 3 of us take turns DMing.  How do I get my characters into the campaign.

So how do I get the other players character's into the campaign.  When they create their characters they only have the grappler feat although the players see the Player's handbook content but don't see things at creation.

Will probably have more questions,I'm old, lol.

In order to share content, and to use that shared content in character creation, characters need to be in the same campaign. To create a campaign, go to the megamenu and hover over 'collections.' Click on 'my campaigns.' Over on the right of the screen there should be a button that says 'create a campaign.' Click on that, set up whatever needs setting up (I've never done that part, others should be able to fill in any questions you have there) and then once the campaign is set up, on the campaign page there should be a link on the right that you can send to players (and the DM can use themselves for NPCs). They use this link to join the campaign and then create a character. If they've already started creating a character that's fine, there's an option to use an existing character, and once it's in the campaign they can edit it to get access to any shared materials.

What's shared? Any WotC D&D publications any person who has a character in the campaign (or created it) purchased on DDB. Note there's a fair amount of free content in the Basic Rules, but the PHB is a purchase, it's not free. It overlaps a fair amount with the Basic Rules, and is probably what your players are seeing at the moment - one subclass per class, a good chunk of the spells, and just the one feat. Homebrewed materials are also shared, but if no one has done any mucking around with that yet there won't be anything to see there.

Sharing only occurs if you (or one of the players) has the right level of subscription.

I have the highest tier subscription but other person does not.  He can see all the content but when he makes a character he does not see the options, for instance he only sees the grappler feat.

Characters have to be made inside of a campaign that has content sharing turned on. It doesn't matter who sets the campaign up, whoever has the Master Tier subscription can toggle content sharing on.

So how do I make someone else's character?  

Quote from Tyris2222 >>

So how do I make someone else's character?  

I'd advise letting them do it themselves, as per pocketmouse's explanation above. If you insist though: go to the campaign, create an unassigned character, send that person the invite link and tell them to claim it. 

1. Click on the my collections, choose my campaigns, then click create a campaign button.   On the next screen name it and put in a basic description and hit create campaign button at the bottom.  Then it will appear in my campaigns list.  Choose to view that campaign and there will be a big blob of web address thing with a link to send to your players send that link.

Quote from Tyris2222 >>

So how do I make someone else's character?  

You don't have to. Send them the invite link for the campaign and they can roll up a new character or bring in a preexisting one and edit it within the campaign.