For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:fusionfuture:office/openSUSE_Tumbleweed/home:fusionfuture:office.repo
zypper refresh
zypper install wps-office
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:fusionfuture:office/15.6/home:fusionfuture:office.repo
zypper refresh
zypper install wps-office
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:fusionfuture:office/15.5/home:fusionfuture:office.repo
zypper refresh
zypper install wps-office
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:fusionfuture:office/15.4/home:fusionfuture:office.repo
zypper refresh
zypper install wps-office