bexio gives you the option of defining your number ranges in such a way that each new year starts out with the same number. These number ranges are called yearly number ranges. The important thing to keep in mind is that these need to be defined in the previous year, otherwise the new numbering will not work. The following article explains how you can define these yearly number ranges.
Open the document settings under: "Settings - All settings - Functions & modules". Then click the desired document under "Document types - Default settings" to change its defaults.
Then click the checkbox "Restart every year" in the overview of the desired document type and press "Save" to confirm the change.
You will then be forwarded back to the document settings. There you need to click the menu item "Specify number ranges" in order to define the number ranges.
In the next menu you can then assign the number ranges as desired for each year and then accept the entries by pressing "Save".
If you want to make this change for all documents in "Sales" ("Offers", "Orders", "Invoices", etc.), you must change them individually as demonstrated in the example.