What game system are you using? Are you using Roll Templates or a particular Character Sheet?
I'd like to direct you to my Pathfinder Macro Example page:
https://wiki.roll20.net/Macros_-_Pathfinder_Exampl...In-Line Roll Example, using Power Attack and a two-handed weapon in Pathfinder:
/me grips his GreatSword firmly and swings powerfully!
[Crit:19-20/x2]
H1:[[1d20cs19 + 5 -1[PowerAttack] + ?{Misc Bonus/Penalty?|0}[Misc. Bonus] ]] for [[2d6 + 6[STR*1.5] + 3[PowerAttack] + ?{Damage Bonus?|0}[Misc. Bonus] ]] Dmg
C1:[[1d20 + 5 -1[PowerAttack] + ?{Misc Bonus/Penalty?|0}[Misc. Bonus] ]] for addt'l [[2d6 + 6[STR*1.5] + [PowerAttack] + ?{Damage Bonus?|0}[Misc. Bonus] ]] Dmg
H2:[[1d20cs19 + 5 -1[PowerAttack] -5 + ?{Misc Bonus/Penalty?|0}[Misc. Bonus] ]] for [[2d6 + 6[STR*1.5] + 3[PowerAttack] + ?{Damage Bonus?|0}[Misc. Bonus] ]] Dmg
C2:[[1d20 + 5 -1[PowerAttack] -5 + ?{Misc Bonus/Penalty?|0}[Misc. Bonus] ]] for addt'l [[2d6 + 6[STR*1.5] + 3[PowerAttack] + ?{Damage Bonus?|0}[Misc. Bonus] ]]
Roll Template Example: (broken into multiple lines for readability; the macro would be entered as a single non-breaking line of text)
&{template:default} {{name=Melee Attack}}
{{Attack1:=[[1d20cs>17 + 5[STR] + 12[BAB] +3[WeaponBonus] + ?{AttackMod|0} ]] for [[1d8 + 5[STR] + 3[WeaponBonus] + ?{DamageMod|0} ]] Dmg}}
{{Confirm1:=[[1d20 +4[CritFocus] + 5[STR] + 12[BAB] +3[WeaponBonus] + ?{AttackMod|0} ]] for [[1d8 + 5[STR] + 3[WeaponBonus] + ?{DamageMod|0} ]] Crit Dmg}}
{{Attack2:=[[1d20cs>17 -5[BABPenalty] + 5[STR] + 12[BAB] +3[WeaponBonus] + ?{AttackMod|0} ]] for [[1d8 + 5[STR] + 3[WeaponBonus] + ?{DamageMod|0} ]] Dmg}}
{{Confirm2:=[[1d20 -5[BABPenalty] + 5[STR] + 12[BAB] +3[WeaponBonus] + ?{AttackMod|0} ]] for [[1d8 + 5[STR] + 3[WeaponBonus] + ?{DamageMod|0} ]] Crit Dmg}}