A telescope works perfectly well in daylight and using one is the best way to learn the instrument without the frustration of the dark. There is exactly one thing it must never be pointed at, and everything else on the horizon is fair game.
The rule first
Never point a telescope, a finder or a pair of binoculars at the sun without a filter fitted over the front aperture. Concentrated sunlight causes immediate and permanent retinal injury and will also destroy a camera sensor. If you observe in daylight, cap the finder before you start so nobody uses it by habit.
Why daylight practice is worth doing
Everything that is fiddly in the dark is easy in the light: aligning the finder with the main tube, learning where the focus point is, discovering which eyepiece gives which field, finding out how much the mount shakes and how long it takes to settle. Half an hour on a distant chimney pot saves an hour of fumbling on the first clear night.
What daylight actually shows
Distant buildings, hills, ships and birds, at magnifications no spotting scope reaches. Two things surprise people: the image in an astronomical telescope is usually upside down or mirrored, which is harmless for stars and disorienting on a landscape, and atmospheric turbulence over warm ground is far worse in the afternoon than at night, so the view boils above about 60x.
Questions people ask about telescope
Can you use a telescope during the day?
Yes, for anything on the ground or in the sky except the sun. It is the best way to learn the instrument before your first night with it.
Why is the daylight image upside down?
Because astronomical telescopes omit the extra optics that would invert it, which would cost light and sharpness. It matters not at all on stars and looks odd on a landscape.
Can I look at the moon during the day?
Yes, and it is a good target: the moon is often visible in a blue sky and shows perfectly well, with lower contrast than at night.