PHIn most cases, yes, you can.
However, “complete” has the connotation of filling out something to make it a complete whole, where “finish” can mean just “bring something to an end.”
In the following examples, the second one does not work.
“I just finished breakfast.” vs. “I just completed breakfast.”
“Diamond earrings completed the set.” vs. “Diamond earrings finished the set.”
“They finished eating in silence.” vs. “They completed eating in silence.”
“I haven’t finished the dishes yet.” vs. “I haven’t completed the dishes yet.”
“She finished her oatmeal and poured herself a cup of coffee.” vs. “She completed her oatmeal and poured herself a cup of coffee.
However, “complete” has the connotation of filling out something to make it a complete whole, where “finish” can mean just “bring something to an end.”
In the following examples, the second one does not work.
“I just finished breakfast.” vs. “I just completed breakfast.”
“Diamond earrings completed the set.” vs. “Diamond earrings finished the set.”
“They finished eating in silence.” vs. “They completed eating in silence.”
“I haven’t finished the dishes yet.” vs. “I haven’t completed the dishes yet.”
“She finished her oatmeal and poured herself a cup of coffee.” vs. “She completed her oatmeal and poured herself a cup of coffee.