I don't play blindfold, but I do know that Arena has a setting to allow keyboard entry of moves:
In the menu, it's "Options --> Appearance --> Chessboard --> Move Input", then check option "Enable move input with keyboard".
Regarding blind fonts - I don't think Arena is supplied with blind fonts, but I installed the blind fonts that were supplied with my old Fritz 8 DVD, and since the fonts are installed in Windows, they are also available to Arena.
I've been looking for -and found (details below)- a computer chess program that allows keyboard move input (or mouse) instead of only allowing mouse-moves-the-pieces input as Chess King, Lucas Chess, Arena, etc. do.
If anyone knows of a better solution, please reply.
The idea is to practice and improve my weak ability at Blindfold Chess by typing my moves and seeing my opponent's moves only in algebraic notation while covering up the part of the screen containing the board, then keep track of the board in my head. If I get stuck, lost, etc. - I can briefly remove whatever's covering the board to get back on track.
I found that the old Fritz 5.32 (Fritz532.zip) engine+GUI that's available and legally free at many internet sites allows you to input moves via keyboard in abbreviated algebraic notation. The board is shown on the top left of the computer screen (so hanging a folded paper sheet on top of my laptop screen will cover it), the window for typed-input is underneath the board, and the game score is on the right of the screen. Small, popup-windows with Coach hints (if you want to play with the coach - which could help you if you're having trouble visualizing the position) with it's hints about watch out for your opponent's pawns, etc.) or asking for clarification if you take-back a move, etc. do NOT appear over the board, so covering the board doesn't impede playing the game in any way.
If you try Fritz 5.32 on a newer Windows computer (I have Win 10), right-click on the 532Setup.exe file, choose, "Properties," then select the "Compatibility" tab. Click to set a check mark in the box reading "Run this program in compatibility more for:" and from the drop-down box beneath it choose "Windows XP Service Pack 3." When the setup program (in German - the program itself can be set to run in English or other languages) wouldn't initially run for me, Windows did a compatibility check and recommended the XP Service Pack 3 - and it worked fine.
The real goal is to improve my ability to calculate in my head, both through better visualization and better speed, while playing and it's said that being better at blindfold chess helps.