Template talk:Welcome

How to use the template
Just type on a user's Talk page then add your signature. As soon as you Save, the entry will lose its link to the template and become ordinary text, which you can edit to personalise it.

Use of "subst:" prefix
Using the prefix before any template name copies the template then cuts the connexion. If you omit the "subst:" the result copies just the same but will not be editable and will always show the current version of the template - probably not a good idea for a one-off welcoming message although it is useful for many other templates.

Edit it to make it more specific to the wiki
For example, it could say "Welcome to the  XYZWV Wiki ". Maybe add a link to a page you particularly want new users to look at.

Make another one just for you to use
On your user page you could create a link to something like template:welcJG then make the resulting page a copy of template:welc and modify it any way you like. Then you can type or paste on a newcomer's page and not need further personalising.