Children should wear احرام garments with leniency applied — the parent makes niyyah for young children, and no fidyah is required if children violate احرام restrictions.
Children can and should wear احرام garments when performing حج or عمرہ, following the general rules with appropriate leniency for their age. For boys, this means the two white unstitched garments (izar and rida) similar to adult men. Small احرام garments sized for children are readily available in shops near the Haram. Girls wear their normal modest clothing, as women's احرام does not require specific garments.
The parent or guardian makes the intention (niyyah) on behalf of a young child who cannot understand the concept. For older children who understand, they should be encouraged to make the intention themselves with parental guidance. Regarding احرام restrictions: if a child covers their head (boys), uses scented products, or otherwise violates احرام restrictions, no fidyah (penalty) is required جمہور علماء کے مطابق. This is based on the hadith: 'The pen is lifted from three: the sleeper until they awake, the child until they reach puberty, and the insane until they recover' (Abu Dawud). However, parents should still teach children proper احرام etiquette to the extent their age allows.
Source: Sunan Abu Dawud; al-Nawawi, al-Majmu'; Ibn Qudamah, al-Mughni