You can can plain strawberries on their own, as plain fruit, with or without sugar. These directions appear in the Ball Blue Book, the Bernardin Guide, and in the Ball / Bernardin Complete. Note that you may not be happy with the quality; they get quite mooshy.
Hull the berries (i.e. remove green caps & stems.)
Leave whole; don't slice or chop.
Put in a large pot.
If using sugar, measure: for each 1 litre / quart of whole berries by volume add 125 to 175 g (½ to ¾ cup / 4 to 6 oz) white sugar. Stir fruit to distribute sugar evenly. Cover pot; let stand in a cool place for 5 to 6 hours.
If NOT using sugar. See recipe notes.
Heat pot slowly on a medium-hot burner. Stir frequently. Heat until berries are warm all the way through and, if using sugar, all sugar is dissolved. (No more, you don't want them to break down into syrup or jam).
Pack strawberries and liquid into heated jars.
Leave 2 cm (½ inch) headspace.
Debubble, adjust headspace.
Top up with clean boiling water from a kettle if insufficient liquid.
Wipe jar rims.
Put lids on.
Process in a water bath or steam canner.
Process ½ litre (US pint) jars for 10 minutes; litre (US quart) jars for 15 minutes. Increase time as needed for your altitude.