Is it permissible to supplicate for the deceased, after the third Takbir in the funeral prayer, with what the worshiper deems good for them, due to not memorizing the recommended supplications?

Supplicating for the deceased is obligatory according to scholars, and sincerity in it is required. It is preferable to use the supplications transmitted from the Prophet, peace and blessings be upon him, such as: "O Allah, forgive him, have mercy on him, grant him well-being, and pardon him..." If the worshipper does not remember a transmitted supplication, it is permissible for him to supplicate with any wording that serves the purpose.