There are many people claiming at the time Pelé was playing many of his matches werent recorded so it's impossible to know.
However, there are also many well known soccer websites claiming assist statistics for particular sections of his career, such as the world cup, which were likely all recorded in tv and can be counted.
For all the world cup editions he played in, it's stated that he scored 10 assists
Top 5 players with the highest numbers of assists in the FIFA World Cup
List of international goals scored by Pelé (it also mentions World Cup assists)
Transferkmarkt which is several times mentioned in sports networks and media mentions 8 assists in Copa Libertadores and international cup Pelé assists in Copa libertadores and international cup
This verified Twitter account and other soccer website news claim Pelé had
47 assists in Brazil national team . They dont clarify however if it includes friendly unofficial matches or not, since this figure conflicts another.
Neymar has now surpassed Pelé in Brazil
This other source claims 18 assists in New York Cosmos in 1976
Pelé assists in 1976 in Cosmos
So, I dont have the full detail of how all Pelé assists were obtained, but spanish Wikipedia claims 305 (69 in first division, 192 in regional division, 11 for international cup and 33 in national team) . Pelé assists spanish Wikipedia , and this figure equals the figure given in this english Quora answer which adds up to the same number but with a different breakdown (245 assists in 656 games for Santos; 27 assists in 64 games for New York Cosmos; 33 assists in 92 games for Brazil.) How many assists did Pelé have
Even though this last source isnt considered reliable and it's unsourced, considered both different breakdowns, by different persons, in different languages (one by clubs and the other by tournaments) add up to the same number, and in the first case the figure it's a breakdown reviewed by many, I think it's needed to mention it and the best answer we can have up to today.