The SPF is to reduce the possibility of spoofing by publishing in the DNS a record (of type TXT) indicating which IP addresses are allowed or prohibited to send mail for the domain in question
Depending on your environment, the value to include is :
Office 365 and Google environment:
Physical environment (Exchange On Premise):
Below is an example SPF record where the value is inserted between v=spf1 (beginning of SPF field) and -all (end of SPF field), the SPF record is type TXT:
v=spf1 include:spfcloud.letsignit.com ~all
BE CAREFUL :
If no SPF value exists for your domain, make sure that no other third-party service sends emails on your behalf before creating a SPF to declare Letsignit.
If an SPF record is already present for your domain, add it after the other records (separated by a space).
Remember to check the number of records in your SPF record. (Maximum limit of 10 records).
For any further questions, do not hesitate to contact us via our online chat :)