Do i need to purchase iso 15223-1 in order to comply with a medical device app?
Yes, you need to purchase this standard. But please be careful because the new revision of this standard is currently under development: ISO/DIS 15223-1 Medical devices — Symbols to be used with medical device labels, labeling, and information to be supplied — Part 1: General requirements.
There are some new symbols that are applicable to all medical devices, regarding the type of medical device.
Furthermore, can the iso 13485 certification and the CE certification be done by the same organization?
Yes, both certifications can be done by the same Notify body, moreover, it is recommended and expected.
The following article regarding compliance with the MDR requirements for medical device labels can be helpful: