If you have a backyard planted with flowers and plants, then attracting birds should not be a problem.
They will come willingly. However, if you don’t have one, it might be a little struggle to invite them in.
With window feeders, you reduced the waiting time by half. The feeder is within their flying vision, so they will see it fast enough.
Some birds are also attracted to certain colors so putting colorful seeds or colorful nectar containers will eventually get the birds over to your window.