Draw the structure of the following molecules: (i) XeOF4 (ii) H3PO3

(i)
Xe has 8 valence electrons. O contributes 6, and each F contributes 7, giving a total of 34 electrons. Xe is the central atom and forms 5 bonds with one O and four F atoms. The remaining 26 electrons are placed as lone pairs; 6 on O, and 20 on F (5 pairs each). The structure is square pyramidal with one oxygen double bonded to the Xenon.

(ii)
The structure of H3PO3 is more complex and the correct drawing depends on whether you're showing the structure of the acid or its conjugate base. In the acid form, a phosphorous atom is centrally bonded to 3 oxygens (one with a double bond, and two with single bonds). Each of the singly bonded oxygens is also bonded to a hydrogen. The phosphorous atom has a lone pair of electrons, as it has a formal charge of 0. It is a trigonal pyramidal structure.
(This is a picture from wikipedia to illustrate the structure)
Note that there are possible resonance structures, but the depiction above is the most common.