After becoming a public prosecutor, she has held various positions related to the functions of the Public Prosecutor's Office in Spain, many of which were positions of responsibility.

She holds the Cross of Honour of Saint Raymond of Peñafort, the Silver Cross of Merit from the Civil Guard and the Cross of the Order of Police Merit with white badge of the National Police Corps.

From 2000 and 2004, as Chief Prosecutor of the Public Prosecutor's Office of the High Court of Justice of Madrid, she carried out continuous coordination of the on-call Public Prosecutor's Office in the Spanish capital.

On 1 July 2004, Ms. Tejada was appointed Chief Public Prosecutor of the Office of the Attorney General’s Technical Office, a position she held until 11 July 2011. Also, during this time, she held the position of Eurojust National Correspondent for terrorism. In this role, she participated in the annual Eurojust correspondent meetings held in The Hague, as well as in the various anti-terrorism working groups in which the Spanish Prosecutor's Office was involved, together with those from other countries like France, the United Kingdom, the United States or Morocco.

By Decree of the Prosecutor General of 1 April 2011, she was appointed Public Prosecutor against Cybercrime, which was renewed on 24 February 2017. In this role, she has been responsible for coordinating all actions of the Spanish Public Prosecutor's Office regarding cybercrime at the national level, as well as structuring, implementing and managing the network of specialized prosecutors in this area.

Likewise, from December 2012 to April 2015, Ms. Tejada combined this function with that of the Deputy Public Prosecutor for the Criminal Protection of Equality and against Discrimination, which she was appointed to in a Decree dated 12 December 2012.

Since 2012 she has represented Spain in the biannual T-CY meetings of the European Council’s Budapest Convention on Cybercrime and has joined the Cybercrime Expert Group meetings convened by the UN in Vienna in February 2013 and March 2019. In Spain, she has participated in numerous Working Groups for developing the implementation plans of the Spanish National Cybersecurity Strategy published in December 2013.

Since 2019, Ms. Tejada has been permanent member of the Law Commission’s Fifth Section of Procedural Law and holds, among others, the degree corresponding to the 52nd specialized course from the Higher Centre for Advanced National Defence Studies (CESEDEN in Spanish) on "The New Threat of the 21st Century. Cybersecurity and Cyberdefence: Strategies, Capability and Technologies", developed in September-December 2013.

She participates in multiple institutional and educational activities, both nationally and internationally. The educational training actions aimed at legal practitioners and researchers are particularly noteworthy. She has also authored numerous publications on fighting cybercrime.