What is the ruling on an employee (guard) taking and using property no longer used by the company, or neglected by employees, without the permission of the officials in charge? And what is the ruling on using general office supplies at work, such as pens and papers, for personal use? And how can one atone for this sin?

Firstly: It is permissible to take discarded items that people no longer want, such as faulty headphones or items thrown away by employees, unless it is evident that they were left behind by mistake.

Secondly: The jacket you found in the mosque should be treated as a luqatah (found item). If it is worn out and worthless, there is no harm in taking it. However, if it has value, you must announce it for a year. If a year has not yet passed since you took it, you must complete the announcement period and then donate its value on behalf of its owner. If the owner appears, offer him the choice between having the charity be for him or receiving the value of the jacket. As for the charger, if you strongly suspect that an employee forgot it, you must ask him about it. Otherwise, it is a luqatah and the same rules apply to it as apply to the jacket.

Thirdly: It is permissible to use stationery items that are not consumed by use, such as rulers and computers. However, it is not permissible to use items that are consumed, such as pens, paper, and ink, unless with the owner's permission. Therefore, you must repent and return the value of what you took without his knowledge.