A template campaign is an ordinary campaign that you build to be copied from. There is no special campaign type and no setting that turns one on. It is a campaign you never actually play in.

Templates are worth the effort if you run several campaigns in the same game system, or if you set up campaigns for other people.

Building one

1. Create a new campaign and give it a name that makes its purpose obvious, such as "Template — 5e" or "House Rules Master".
2. Build the parts you want to reuse: your Ability Types, Stat Groups, Currencies, Item Library and any NPCs or Entities that turn up in every game you run.
3. Keep it tidy. Everything in the template gets copied, so anything half-finished is copied half-finished.
4. Clone from it into each new campaign, following the order in 5.2.

Keeping it up to date

When you improve something in the template, you can push that change out to the campaigns you built from it. Clone the section again with Overwrite previously cloned data? ticked. Read 5.3 first — Overwrite also replaces any changes you made to those records in the campaign you are updating.

Building a template for someone else

The Copy to campaign list only offers campaigns you own, so you cannot set up another person's campaign for them by cloning it yourself. Instead, turn on Allow cloneable data? in your template's settings and add them to it as a player. They can then clone from your template into their own campaign. 5.5 covers this.