This study is a Phase I, single center, randomized (Parts 1 and 2 only), open-label, 3 part study. Parts 1 and 2 are 2-way crossover, with 1-fixed sequence, 3-period designs to investigate the effect of formulation, food and rabeprazole on the PK of GDC-0853 in healthy male and female (of non-childbearing potential) participants. Part 3 is a fixed-sequence study with 3 treatments to characterize the steady-state PK of the GDC-0853 tablet; the effect of simultaneous administration of a single dose of methotrexate on the steady-state kinetics of GDC-0853; and the effect of dosing GDC-0853 to steady-state on the single dose PK of methotrexate in healthy male participants.