Education does not improve the live of the characters in this novel. There are absolutely no examples of lives being improved through education.
The missionaries who travel to Africa with the intentions to educate the Olinka tribe according to western standards fail to help the tribe when their land is taken from them and their livelihoods destroyed. The one person they seemed most likely to help ends up undertaking the ritual scarring and female circumcision that the missionaries tried to help eliminate. Though Tashi was "educated", she was not helped.
Nettie, Celie's bright and educated sister, fails in her efforts to help the Olinka, despairs over the hurt she causes to Corrine, and generally is unaided by her education in her efforts.
Celie is not educated. She is literate, but this is the extent of her education. While she is able to find some solace in writing letters, this is not exactly a benefit of education, per se.
Schooling plays only a tangential role in the narrative of the novel and education is not depicted as salvational or especially helpful.