On this page you will find all the information related to travel to Tenerife and staying on the island during the current Covid-19 situation. Travellers and tourism sector professionals can use it to check health and safety protocols, and regulations.
The current Spanish regulations for international passengers entering the island, as established by the provision of December 11, 2020, can be consulted in full at the link: https://www.boe.es/boe/dias/2020/12/11/pdfs/BOE-A-2020-15951.pdf
For more information about travel to the Canary Islands and between islands, see this detailed info page from: Canary Islands Tourism.
In this link of the Government of Spain you will find all the information related to the procedures and requirements to travel to Spain.