MSISDN means Mobile Station International Subscriber Directory Number and it’s a number used to identify a phone number internationally. It is composed of the country code and the national destination's code. The MSISDN format will get rid of the + sign and of any 0 before the mobile number.
MSISDN = CC + NDC + SN
CC = Country Code
NDC = National Destination Code, identifies one or part of a PLMN
SN = Subscriber Number
For example, in Switzerland, you would dial 079-383-4315 to call a mobile phone.
In the MSISDN format, you would dial 41793834315
Adding the country code and getting rid of the 0 before the mobile phone.
Check out our Phone Country Code List if you are not sure what your country code is.
When importing your cell phone list you can either use the MSISDN format, or you can use the +. However note that we only store it in the MSISDN format.