Am I required to write the calculator model name on my paper?

I have seen on TikTok that I am required to write the calculator model I have used ?? Teachers has not told me this, is it true? will i lose marks?

You're being told one thing by random strangers on TikTok and another thing by you own qualified teachers, and you want to know who to believe? Have I got that about right?

The official rules (from the Joint Council for Qualifications, which covers all the UK exam boards) are detailed in section 10 of their "Instructions for conducting examinations", here.

Here is the whole of section 10:

"10. Using calculators

10.1 Candidates may use a calculator in an examination unless this is prohibited by the awarding body’s specification.
The instructions on the question paper will say whether calculators are allowed or not. If the instructions do not include such a statement, calculators should be treated as standard equipment and may be used by candidates.
Where the use of a calculator is allowed, candidates are responsible for making sure that their calculators meet the awarding bodies’ regulations.

10.2 The instructions set out in this section apply to all examinations unless stated otherwise in an awarding body’s specification

10.3 Candidates must be told these regulations beforehand and be familiar with the Information for candidates documents.

Calculators must be:
• of a size suitable for use on the desk;
• either battery or solar powered;
• free of lids, cases and covers which have printed instructions or formulae.

Calculators must not:
• be designed or adapted to offer any of these facilities:
• language translators;
• symbolic algebra manipulation;
• symbolic differentiation or integration;
• communication with other machines or the internet;
• be borrowed from another candidate during an examination for any reason;
• have retrievable information stored in them. This includes:
• databanks;
• dictionaries;
• mathematical formulae;
• text.

The candidate is responsible for the following:
• the calculator’s power supply;
• the calculator’s working condition;
• clearing anything stored in the calculator.

10.4 An invigilator may give a candidate a replacement calculator.

10.5 Where access is permitted to a calculator for part of an examination, it is acceptable for candidates to place their calculators on the floor under their desks in sight of the invigilator(s) for the non-calculator portion of the examination."

Note that there is no mention of any requirement to write down the calculator model number anywhere.

Clause 10.2 says that an exam board might have it's own additional rules. You can see those for Pearson/Edexcel here. What exam board are you using?