Pages intended to be reused as portions of other pages are called templates. The names of template pages start with the prefix Template:. A template can be included on another page using the syntax {{Page name}} (including the curly brackets), but leave out the Template: prefix between the curly brackets!
If you wish to make a personal boilerplate (such as a personalized welcome message, or the like), you make it in your own userspace. Simply create the page as a subpage of your userspace (in the format User:Foo/something). To put it onto a page, use the curly brackets as usual, but remember to use the syntax {{User:Foo/something}} rather than {{something}}. This is because the curly-bracket syntax automatically looks in the Template namespace, so if you want to use one from your own userspace, you need to tell it to look there.
To add this auto-updating template to your user page, use {{totd}}
Global Microscope currently resides in the Rocky Mountain region of the USA. She has a BS in Geology from the University of Houston (1997) and an MS in geology (2002) from The University at Albany, SUNY. Her research interests have included, but are not limited to igneous textural evolution, impactites and helium geology.