Answer
Based on official Jordanian legal texts
A lineage claim may be filed by anyone holding a legitimate, direct interest in establishing it — an interest the judge assesses on the facts of each case. The main holders of standing in practice:
The mother
The most frequent claimant in practice: in her personal capacity for matters of her own marriage (marriage confirmation), and as representative of her minor child in seeking to establish the child's lineage from the father — especially upon denial or after an undocumented marriage.
The child
Lineage is the child's right before anyone else's. Upon reaching majority, the child may sue personally to establish lineage from the father, even if the family failed to act earlier — the right to lineage is not lost by neglect.
The father
The father himself may be the claimant: for instance, to establish his child's lineage from an urfi marriage that the wife's family refuses to recognize, or to correct official records that were never properly registered.
Heirs and interested parties
In certain situations, a claim may be admitted from someone with a recognized interest, such as heirs — to confirm or contest a legal position affected by lineage, like inheritance entitlement — subject always to the court's assessment of standing and interest.
On the other side: the defendants
The claim is brought against the denier — usually the father, or his heirs after his death — with minors represented in the proceedings according to the rules.
Who files, in what capacity, and against whom are precise questions that affect the claim's formal admissibility before its merits are even examined; settle them with a specialized lawyer from the outset.
This is a general answer based on available Jordanian legal sources and does not replace advice from a specialized lawyer in an actual dispute.