Is it permissible to continue working as a secretary for a manager who commits indecency in the office, and is the secretary sinful if he continues to work with him?

It is not permissible to work with those who commit sins in matters that contradict the Shari'ah. However, if the work itself is permissible and their sins are separate from it, there is no objection, provided one avoids their sins and close companionship with them. It is advisable to counsel the person committing the sin to fear Allah, unless there is a fear of harm that would be difficult to endure. If they do not respond, it is preferable to seek employment with the pious, for the Prophet, peace be upon him, said: "Do not accompany anyone but a believer, and let no one eat your food but one who is pious." If advice has been given and they do not respond, their sin will not harm you, for Allah Almighty says: "O you who have believed, عليكم أنفسكم لا يضركم من ضل إذا اهتديتم" (O you who have believed, upon you is [the responsibility for] yourselves. No one who errs will harm you when you have been guided.)