Full funding normally includes full tuition and a stipend for living expenses for the four to six years a student is in the doctoral program. In most cases, doctoral students are expected to serve as graduate teaching or research assistants in exchange for the awards. This responsibility is typically complementary to your PhD research and provides students with teaching experience.

https://www.profellow.com/fellowships/how-to-fully-fund-your-phd/

...when considering a doctorate, research all the potential PhD programs in your academic field, including small and lesser-known schools both in the U.S. and abroad, and ask the admissions office if they fully fund every admitted student. This may have a major impact on the schools you consider applying to....

...a PhD stipend may be substantially less than what you are earning in the private sector. Yearly stipends normally range from $18,000 – $30,000. Small cities and towns have lower costs of living, so another major factor in your consideration should be location...

https://www.profellow.com/fellowships/how-to-fully-fund-your-phd/