This is how one can prompt for user input in a Makefile (credit: https://stackoverflow.com/a/47839479)

Makefile

.PHONY: help
help: ## Shows the help
        @echo 'Usage: make <TARGETS>'
        @echo ''
        @echo 'Available targets are:'
        @echo ''
        @grep -E '^[ a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | \
                awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
        @echo ''
        @echo ''

.PHONY: prompt-apply
prompt-apply :
	@( read -p "Apply? [y/N]: " sure && case "$$sure" in [yY]) true;; *) echo "Skipping apply"; false;; esac )

.PHONY: deploy 
deploy : diff prompt-apply ## Recompile, show configuration diff, and apply
	@echo "APPLY"