"While the Psalms are used extensively in worship and prayer, the original intent was as a vehicle to teach, explain, encourage, and communicate with the individual listener as well as the entire people, hence their public performance. Today we have some knowledge as to which Psalms were sung on specific days or occasions, but we do not know the entire schedule.
Some of the titles given to the Psalms in their ascriptions suggest their use in worship:
Some bear the Hebrew designation shir (Greek ode, a song). Thirteen have this title. It means the flow of speech, as it were, in a straight line or in a regular strain. This title includes secular as well as sacred song.
Fifty-eight Psalms bear the designation (Hebrew) mizmor (Greek psalmos, a Psalm), a lyric ode, or a song set to music; a sacred song accompanied with a musical instrument.
Psalm 145, and many others, have the designation (Hebrew) tehillah (Greek hymnos, a hymn), meaning a song of praise; a song the prominent thought of which is the praise of God.
Tehillah is also the singular of the name of the book in Hebrew, Tehillim. Six Psalms (16, 56‚Äď60) have the title (Hebrew) michtam. Psalm 7 and Habakkuk 3 bear the title (Hebrew) shiggaion." (Wiki)