Next year I plan to work in Osaka.

Literal

Next-year I [topic-は] Osaka [at-で] work [intention-つもり] is.

~つもり ('intention') attached to a plain-form verb expresses the speaker's plan or intention — つもりだ / つもりです in polite. Distinct from ~予定 (objective schedule) or ~ことにする (decision). Personal intent.