Thoroughly wash strawberries - I like to soak them in water and vinegar solution (3 parts water with 1 part white vinegar) for at least 5 minutes. Thoroughly rinse the ripe strawberries under running water. Lay them on a clean towel or paper towels and pat dry to remove excess moisture.
You can freeze the strawberries whole or sliced, which is what I prefer. Once frozen, they will be hard to slice.
Spread the strawberries in a single layer on a parchment-lined baking sheet. Make sure they're not touching each other. Place the baking sheet in the freezer and let the strawberries freeze for a few hours until firm.
Once the strawberries are frozen, transfer them to a freezer-safe container or bag. Try to remove as much air as possible to prevent freezer burn. If using storage bags, stick a straw into a little opening and suck all the air out.
Notes
When properly stored, they can last for about 8-12 months in the freezer. Avoid repeated thawing and refreezing.