Commonly used Repeat Text Indications are included in the editors to assist you.
iOS, Android - Tap on the horizontal lines icon in Text edit mode (ABC mode) (iOS - 3 lines, Android - 4 lines) and it will present you with a list of commonly used texts (e.g. D.C. al Coda, D.S. al Coda and repeat times) that are also understood and interpreted by the Player, or in the Text box, type in the text if you are familiar with the exact spelling.
Mac edit mode - click the down arrow to the right of the Text box for the text options, or type in the text if you are familiar with the exact spelling.

Use the two arrows on the right to move the text up or down.

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They follow standard music notation rules. Below are the details for each supported text.

D.C.
D.C. al Fine also needs a Fine to indicate where the form ends. This results in an ABA form.
D.C. al Coda also needs a coda sign and an actual coda. 
D.C. al 2nd ending also needs a Fine to indicate where to stop after going to the 2nd ending. This goes back to the top but then skips the 1st ending and goes straight to the 2nd ending.

D.S.
The previous three examples also apply to D.S. (Dal Segno) but with the inclusion of a Sign (Segno).
D.S. al Coda needs a Sign, a Coda symbol and a Coda.

A final barline or closing double barline (right double barline) must be used at the right end of both the "fine" measure and the measure where the D.C. or D.S. text is.

x times Repeat
Tap/click on the last beat in the repeating section and select the repeat times from the drop down menu.

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More about the Coda: