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Congratulations on your raised bed gardens.

Raised bed gardening is a very popular way to garden, for many reasons, not least of all is that you have control of the type of soil in your bed.

I have included the following websites for your use:

https://extension.umd.edu/hgic/topics/soil-fill-raised-beds

https://thetinylife.com/how-to-prepare-soil-for-vegetable-gardens/

https://www.canr.msu.edu/news/starting-a-raised-bed-garden

The most highly recommended soil mix is a topsoil to compost blend at a 2 to 1 ratio. 

With that being said, know that not all topsoil is created equal.  Quality topsoil is important and means that your soil has the proper balance of nutrients and the right consistency.  A good quality topsoil is a loamy mix of sand, silt and clay.  So whether you are buying bagged or bulk topsoil, make sure you investigate it thoroughly.  The following information about topsoil might be of some help:

https://www.canr.msu.edu/news/the_shocking_truth_about_topsoil

Compost injects vital nutrients and organic matter into your garden providing the best environment for your plants to get their best start. Compost feeds the soil.  Following is some good information about composting:

https://web.extension.illinois.edu/compost/process.cfm

Nutrients (fertilizers - feed the plants) can be added to this mix (a soil test is the best way to find out what to add) to ensure that your soil has the capacity to provide for the continued growth of your garden. 

One more thing:  those strawberries are perennials and will need rich soil with lots of organic matter and a slightly acidic pH (between 5.5 and 6.5).  Work in compost, rotted manure and peat moss at planting time.

Best of luck to you in your raised bed gardening adventures!