8845 have 10 programmable button which you can utilize for speed dial. You can set up speed dial from Self care portal or directly from CCM page. Make sure you are selecting the sequence number 6-10 to appear the speed dial on right right side and label button is selected.
For more information you can refer Data sheet :
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If you are using a CUCM server, you will need to enable Enhance Line Mode on the Phone to have available the right side 5 softkeys.
Please be aware that not all features are available when on ELM: https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cuipph/8800-series/english/adminguide/P881_BK_C136782F_00_cisco-ip-phone-8800_series/P881_BK_C136782F_00_cisco-ip-phone-8811-8841_chapter_01011.html#reference_B79D0A49A50063E00AFD61EA83CC1D0C
Let me know if CUCM is the case,